(1) Field of the Invention
The present invention relates to a water draining structure for a built-in type motor to be integrally mounted on an automotive throttle body, for example.
(2) Description of the Prior Art
Generally speaking, if water and/or steam (as will be shortly referred to as "water") steals into a motor, it may be reserved in the motor without being drained to the outside and may rust the motor components such as a rotor or a stator to deteriorate the motor functions.
Thus, one of us has proposed, in Japanese Utility Model Laid-Open No. 34854/1989, a water draining structure for a motor, in which a confined chamber is formed between a mounting member such as a housing of a driven device and the motor, in which communication between the motor inside and the chamber is established through a water draining communication hole and an air vent hole, and in which the chamber has its bottom portion formed with a water draining hole vented to the atmosphere.
In case, however, the automobile runs in puddles or the like to have its mounting member or motor splashed with water, its water draining hole may have its opening closed from the atmosphere. More specifically, the water will flow down, if having splashed the mounting member or the motor, along the outer side faces 51a of the mounting member 51, as indicated by solid arrows in FIG. 1. As indicated by broken arrows, moreover, the water will partially invade into a chamber 53 along the mounting face 52 of the mounting member 51, on which is mounted the motor. The water will flow into water draining holes 54 and 55 until it is drained into the atmosphere from the bottom openings of the holes 54 and 55.
On the other hand, the water having flowed down along the outer side faces of the mounting member 51 may flow around the bottom face and plug the openings of the holes 54 and 55 and may deteriorate its drainage from the space 53 out of the water draining holes 54 and 55.